Waterjet cutting systems, including waterjet cutting systems having light alignment devices, and associated methods

ABSTRACT

Various embodiments of waterjet cutting systems are described herein. In one embodiment, a waterjet cutting system includes a high-pressure water source and a waterjet cutting head coupled to the high-pressure water source via a high-pressure water supply. The waterjet cutting head has an orifice and a mixing tube. The orifice forms a waterjet from the high-pressure water. The mixing tube has an inlet aperture through which the waterjet enters the mixing tube, an exit aperture through which waterjet exits the mixing tube, and a passage between the inlet and exit apertures. The waterjet cutting system further includes a light alignment device operably coupled to the waterjet cutting head. In one aspect of this embodiment, the light alignment device is configured to generate a light beam that enters the mixing tube through the inlet aperture, passes through the passage, and exits the mixing tube through the exit aperture.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application No. 61/278,636, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This application describes waterjet cutting systems utilizing alignment devices, and methods associated with such waterjet cutting systems.

BACKGROUND

Abrasive jet systems that produce high-velocity, abrasive-laden fluid jets for accurately and precisely cutting various materials are well known. Abrasive jet systems typically function by pressurizing water (or another suitable fluid) to a very high pressure (e.g., up to 60,000 pounds per square inch (psi) or more) by, for example, a high-pressure pump connected to an abrasive jet cutting head. The pressurized water is forced through an orifice at a very high speed (e.g., up to 2,500 feet per second or more) to form the water jet. The orifice is typically a hard jewel (e.g., a synthetic sapphire, ruby, or diamond) held in an orifice mount. The resulting water jet is discharged from the orifice at a velocity that approaches or exceeds the speed of sound. The liquid most frequently used to form the jet is water, and the high-velocity jet may be referred to as a “water jet,” or a “waterjet.”

Abrasives can be added to the water jet to improve the cutting power of the water jet. Adding abrasives to the water jet produces an abrasive-laden water jet referred to as an “abrasive water jet” or an “abrasive jet.” To produce an abrasive jet, the water jet passes through a mixing region in a nozzle. The abrasive, which is under atmospheric (ambient) pressure in an external hopper, is conveyed through a meeting orifice via a gravity feed from the hopper through an attached abrasive supply conduit to the nozzle. A quantity of abrasive regulated by the meeting orifice is entrained into the water jet in the mixing region by the low-pressure region that surrounds the flowing liquid in accordance with the Venturi effect. Typical abrasives include garnet and aluminum oxide. The abrasives can have grit mesh sizes ranging between approximately #36 and approximately #320.

The resulting abrasive-laden water jet is then discharged against a workpiece through a nozzle tip (alternatively referred to as a mixing tube) that is adjacent to the workpiece. The abrasive jet can be used to cut a wide variety of materials. For example, the abrasive jet can be used to cut hard materials (such as tool steel, aluminum, cast-iron armor plate, certain ceramics and bullet-proof glass) as well as soft materials (such as lead). A typical technique for cutting by an abrasive jet is to mount a workpiece to be cut in a suitable jig, or other means for securing the workpiece into position. The abrasive jet can be directed onto the workpiece to accomplish the desired cutting, generally under computer or robotic control. It is generally not necessary to keep the workpiece stationary and to manipulate the abrasive jet cutting tool. The workpiece can be manipulated under a stationary cutting jet, or both the abrasive jet and the workpiece can be manipulated to facilitate cutting.

It may be desirable to align an abrasive jet with a reference mark on a workpiece, such as a starting hole or a pre-machined feature. One shortcoming of conventional alignment devices relates to the need to temporarily install the alignment device on the nozzle tip. In this configuration, the alignment device is registered by the exterior surface of the nozzle tip rather than from the nozzle tip bore, which defines the abrasive jet. As the nozzle tip wears, the bore may wear into an oval shape and the exterior surface of the nozzle tip may no longer correspond adequately to the bore. Another shortcoming is that some conventional alignment devices do not perform well on a curved or tilted workpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of a waterjet cutting head configured in accordance with an embodiment of the disclosure.

FIG. 2 is a cross-sectional side view of a waterjet cutting head configured in accordance with another embodiment of the disclosure.

FIG. 3 is a cross-sectional top view of a light alignment device configured in accordance with another embodiment of the disclosure.

FIG. 4 is a flow diagram of a process for operating a waterjet cutting system in accordance with an embodiment of the disclosure.

FIG. 5 is a flow diagram of a process for determining the extent of wear of a waterjet cutting system mixing tube in accordance with an embodiment of the disclosure.

FIG. 6 is an isometric view of a waterjet cutting system which can utilize light alignment devices configured in accordance with embodiments of the disclosure.

DETAILED DESCRIPTION Overview

The present disclosure is directed to various embodiments of waterjet cutting systems for cutting materials, including waterjet systems having light alignment devices for properly aligning a waterjet cutting head with respect to a workpiece to be cut. Certain details are set forth in the following description and in FIGS. 1-6 to provide a thorough understanding of various embodiments of the technology. Other details describing well-known aspects of waterjet cutting systems, however, are not set forth in the following disclosure so as to avoid unnecessarily obscuring the description of the various embodiments.

Many of the details, dimensions, angles and other features shown in the Figures are merely illustrative of particular embodiments. Accordingly, other embodiments can have other details, dimensions, angles and features. In addition, further embodiments can be practiced without several of the details described below.

In one embodiment, a waterjet cutting system includes a high-pressure water source and a waterjet cutting head. The waterjet cutting head is coupled to the high-pressure water source via a high-pressure water supply. The waterjet cutting head has an orifice and a mixing tube. The orifice forms a waterjet from the high-pressure water provided by the high-pressure water source. The mixing tube has an inlet aperture through which the waterjet enters the mixing tube, an exit aperture through which the waterjet exits the mixing tube, and a passage between the inlet and exit apertures. The waterjet cutting system further includes a light alignment device coupled to the waterjet cutting head. The light alignment device is configured to generate a light beam that enters the mixing tube through the inlet aperture, passes through the passage, and exits the mixing tube through the exit aperture.

In another embodiment, a fluid jet cutting system includes a fluid jet cutting head coupled to a fluid supply. The fluid jet cutting head includes a mixing tube that has a longitudinal bore through which cutting fluid is conveyed. The fluid jet cutting system also includes a light alignment device coupled to the fluid jet cutting head. The light alignment device is configured to generate a light beam that passes through at least a portion of the longitudinal bore of the mixing tube.

In a further embodiment, a method of operating a fluid jet cutting system includes generating by a light alignment device coupled to a fluid jet cutting head a light beam. The method further includes directing the light beam at a workpiece through at least a portion of a mixing tube bore of the fluid jet cutting head, and based upon the position of the light beam upon the workpiece, performing a cutting operation.

Wateriet Cutting Systems and Associated Methods

FIG. 1 is a cross-sectional side view of a waterjet cutting head 1 configured in accordance with an embodiment of the disclosure. The waterjet cutting head 1 can be a part of a waterjet cutting system having a high-pressure water source (not shown in FIG. 1) coupled to the waterjet cutting head 1 via a high-pressure water supply 5. The waterjet cutting head 1 includes an orifice 6 and a mixing tube 7. The mixing tube 7 has an inlet aperture 19, an exit aperture 20, and an axial passage 34 (alternatively referred to as an axial bore 34, a longitudinal bore 34, or simply a passage 34 or a bore 34) therebetween. The mixing tube 7 is held in place by a fastener 9 (e.g., a nut or other fastener).

The waterjet cutting head 1 has an abrasive inlet port 3 (alternatively referred to as an abrasive feed port 3, an abrasive inlet aperture 3, or simply a port 3 or an aperture 3) that extends through an external surface 21 of the waterjet cutting head 1. The abrasive inlet port 3 has an approximately 90 degree orientation to the exterior surface 21. In operation, an abrasive supply conduit 2 can be attached to the abrasive inlet port 3 to convey abrasives to a mixing region 22 (alternatively referred to as a mixing cavity 22 or a mixing chamber 22) via a passage between the abrasive inlet port 3 and the mixing region 22.

In operation, high-pressure water (or other suitable fluid) from the high-pressure water source enters the waterjet cutting head 1 through the high-pressure supply 5. The high-pressure water passes through a cavity 31 and then through the orifice 6, which forms a high-speed waterjet. If the abrasive supply conduit 2 is attached to the abrasive inlet port 3, abrasives that are conveyed via the abrasive supply conduit 2 mix with the waterjet in the mixing region 22 to form an abrasive jet. The waterjet or the abrasive jet enters the inlet aperture 19 of the mixing tube 7, travels through the passage 34 and exits through the exit aperture 20 to impinge upon a workpiece 8.

In one aspect of this embodiment, the waterjet cutting system further includes a light alignment device 4. The light alignment device 4 includes a power source 10 (e.g., a direct current (DC) power source such as a battery, an appropriate alternating current (AC) to DC conversion device, etc.). The light alignment device 4 further includes a light source 11. The light source 11 can include a laser diode module that generates a laser beam and/or any other suitable device that can generate light. For example, a laser diode module that operates from 3 volts DC and has an output power of approximately 2 milliwatts (mW) to approximately 5 mW can be utilized. The light source 11 generates or produces a beam of light 16. The light alignment device 4 also includes one or more optical components 12 (e.g., one or more lenses or other optical components) for directing and/or focusing the beam of light 16. The optical components 12 can be set to produce a collimated light beam 16 or a converging light beam 16. The light alignment device 4 further includes a tube 14 (e.g., a rigid or semi-rigid tube) having an optical component 15 (e.g., a mirror or other suitable optical component, having an approximately 45 degree orientation to a longitudinal axis of the tube 14). The light alignment device 4 further includes a switch 13 to allow the light alignment device 4 to be turned on and off.

In operation, the light alignment device 4 can be coupled to the waterjet cutting head 1 by inserting the light alignment device 4 into the abrasive inlet port 3. The light alignment device 4 can be registered to the waterjet cutting head 1 by a device such as an indexing device or other suitable device. The tube 14 extends into the mixing region 22 such that the optical component 15 is positioned directly upstream of the inlet aperture 19 of the mixing tube 7. When the light alignment device 4 is activated by switch 13, the light source 11 generates a beam of light 16 that is directed along the tube 14 and is redirected by the optical component 15 toward the inlet aperture 19. The beam 16 enters the inlet aperture 19, passes through the axial passage 34, and exits the mixing tube 7 through the exit aperture 20. The beam 16 impacts the workpiece 8 at position 17, which indicates the position at which a waterjet produced by the waterjet cutting head 1 will impinge on the workpiece 8. After alignment the light alignment device 4 can be removed from the abrasive inlet port 3 and the abrasive supply conduit 2 can be attached to the abrasive inlet port 3.

In certain waterjet cutting heads 1, the abrasive inlet port 3 has an orientation to the exterior surface 21 that is other than approximately 90 degrees. In such waterjet cutting heads 1, the optical component 15 can be appropriately oriented relative to the longitudinal axis of the tube 14 such that the beam of light 16 can still be directed through the axial passage 34 of the mixing tube 7.

In some embodiments, the light alignment device 4 can include two or more optical components 15 (e.g., two or more mirrors) to properly direct the beam 16 through the axial passage 34 of the mixing tube 7. In some embodiments, a prism (e.g., a glass prism or a prism formed of any other suitable optically transparent and/or optically translucent material) having an angled end portion (e.g., at an approximately 45 degree orientation) can replace all or a portion of the tube 14 and the optical component 15. One advantage of utilizing such a prism is that the prism can offer protection against contamination from dirt or other foreign materials of certain components of the light alignment device 4.

In some embodiments, the waterjet cutting head 1 has one or more other ports in the external surface 21 (e.g., a vacuum assist port, a venting port, etc.). In such embodiments, the light alignment device 4 can be inserted into one of the one or more other ports. For example, the port can be a vacuum assist port configured to be coupled to a vacuum assist device via a conduit, and the light alignment device 4 can be inserted into the vacuum assist port in lieu of the conduit. One advantage of such a configuration is that the need to remove the abrasive supply conduit 2 is obviated.

One advantage of directing the beam 16 via the same path as the waterjet or abrasive jet will travel is that such directing eliminates any offset errors in the alignment and provides accurate alignment regardless of the distance between the mixing tube 7 and the workpiece 8 and regardless of any wear of the mixing tube 7.

FIG. 2 is a cross-sectional side view of a waterjet cutting head 1 configured in accordance with another embodiment of the disclosure. One difference between the waterjet cutting head 1 of FIG. 2 and the waterjet cutting head 1 of FIG. 1 is that, instead of the high-pressure water supply 5 being concentrically aligned with the axial passage 34 of the mixing tube 7, the high-pressure water supply 5 has an approximately 90 degree orientation to the axial passage 34 of the mixing tube 7. The waterjet cutting head 1 includes a high-pressure window 18 secured by a fitting 19 and a seal 20. The window 18 can be made of any suitable optically transparent and/or optically translucent material, such as sapphire, silica and/or glass. The window 18 can have a diameter that enables the window 18 to withstand high-pressure water, such as a diameter that is less than 10 mm.

The waterjet cutting system of which the waterjet cutting head 1 can be a part further includes a light alignment device 4 that is coupled to the waterjet cutting head 1 via the fitting 19. The light alignment device 4 generates a beam of light 16 that travels through a cavity 31 and through the orifice 6. Since the orifice 6 is typically made of sapphire or diamond, which are both transparent materials, the beam 16 can pass through other portions of the orifice 6. If a non-transparent orifice 6 is used, optical component lens 12 can be adjusted to focus the beam 16 on the center hole of the orifice 6. The beam 16 passes through the mixing region 19, enters the inlet aperture 19, passes through the axial passage 34 and exits the mixing tube 7 through the exit aperture 20.

In the embodiment illustrated in FIG. 2, the waterjet cutting head 1 also includes a one-way valve 30 (e.g., a check valve) and an air supply conduit 25 (e.g., a tube or other suitable conduit). Water can sometimes remain in the mixing tube 7 or above the mixing tube 7. Such water has the potential to deflect the beam 16 towards an interior side wall of the mixing tube 7. To eliminate any residual water, it can be desirable to slightly pressurize the cavity 31 above the orifice 6 as well as the mixing region 22 and/or the mixing tube 7 using air and/or other suitable gas. The valve 30 can prevent the high pressure water from escaping, and the air supply conduit 25 can supply air. The air can keep the cavity 31, the mixing region 22, and/or the mixing tube 7 free of any water.

One advantage of the waterjet cutting head 1 of FIG. 2 is that no optical components (e.g., mirrors) are needed to redirect the beam 16. Another advantage is that the light alignment device 4 can be permanently or semi-permanently coupled to the waterjet cutting head 1. Another advantage is that the light alignment device 4 can be coupled to the waterjet cutting head 1 without having to remove an abrasive supply conduit 2. Another advantage is that the air supply tube 25 can provide pressurized air so as to prevent the beam 16 from being deflected.

FIG. 3 is a cross-sectional top view of a light alignment device 4 configured in accordance with an embodiment of the disclosure. The light alignment device 4 includes a housing 33 having a generally curvilinear portion 32. The generally curvilinear portion 32 can be sized and shaped similarly to the portion of the exterior surface 21 of the waterjet cutting head 1 (see e.g., FIG. 1) at the point of coupling of the light alignment device 4 to the waterjet cutting head 1. Such a configuration can permit the light alignment device 4 to closely abut the waterjet cutting head 1. The housing 33 can be made out of any suitable material (e.g., aluminum, plastic, etc.). The housing 33 has two cavities 27 into which suitable fasteners can be inserted so as to couple the light alignment device 4 to the waterjet cutting head 1.

The light alignment device 4 further includes other components (e.g., a light source 11, a power source 10, a switch 13, a lens 12, etc.) which can be generally similar to those described with reference to e.g., FIGS. 1 and 2. The light alignment device 4 further includes a biasing device 21 (e.g., a spring). Actuating the switch 13 can cause the biasing device 21 to touch the power source 10 and complete an electrical circuit. Power source 10 can be insulated from the metal housing of switch 13 by insulating collar 22, and a seal 23 can prevent ingress of foreign objects.

The light alignment device 4 further includes a tube 14 and an optically transmissive rod 24. The rod 24 can be made of any suitable material, such as fused silica, sapphire, or glass. The rod 24 has an optical component 15 at an end portion of the rod 24. The optical component 15 can be formed by polishing an end portion of rod 24 at a suitable angle, such as at a 45 degree angle. Additionally or alternatively, the optical component 15 can include another suitable optical component such as a mirror. The point at which beam 16 leaves the rod 24, after being reflected by optical component 15, can be polished flat to avoid a lensing effect. The rod 24 can be moved axially through the tube 14 to adjust the positioning of the rod 24 in the X direction as well as the rotation of the rod 24 with respect to the tube 14. In some embodiments, after such adjustments, a suitable adhesive (e.g., epoxy) can be utilized to fixedly attach the rod 24 to the tube 14.

The light alignment device 4 also includes two adjustment devices 28 (e.g., screws). The two adjustment devices 28 allow for alignment of the light source 10 in the X direction. Although only two adjustment devices 28 are shown, the light alignment device 4 can include additional adjustment devices 28. For example, the light alignment device 4 can include two additional adjustment devices 28 that allow for alignment of the light source 10 in the Y direction. The adjustment devices 28 can be adjusted so as to ensure that the light beam 16 produced by the light source 10 is concentric with the tube 14. In some embodiments, after such adjustments, a suitable adhesive (e.g., epoxy) can be utilized to fixedly attach the light source 11 to the housing.

The housing 33 has a passage 26 extending through a portion of the housing 33. A tube 25 can be connected to the passage 26 and to a pressurized air source (not shown in FIG. 3). When the light alignment device 4 is coupled to a waterjet cutting head 1, the pressurized air source can supply pressurized air proximate to the tube 14 via the tube 25 and the passage 26.

The light alignment device 4 illustrated in FIG. 3 can be coupled to a waterjet cutting head 1 via fasteners inserted into cavities 27. The alignment of the light source 11 in the X and Y directions can be adjusted, and the alignment of the rod 24 in the X direction as well as rotational alignment can be adjusted. As noted above, the light source 11 and the rod 24 can then be permanently or semi-permanently secured in position via suitable adhesives or other fastening materials. Once properly aligned, activating the switch 13 causes an electrical circuit between the light source 11 and the power sources 10 to be completed, and the light source 11 produces a beam of light 16. The beam of light travels through the rod 24 and is reflected by the optical component 15.

The light beam 16 then enters the mixing tube 7 inlet aperture 19, passes through the mixing tube 7 passage 34, and exits the mixing tube 7 exit aperture 20 to impact a workpiece 8 (FIGS. 1 and 2). Pressurized air can be supplied via the tube 25 and the passage 26 to keep the mixing tube 7 axial passage 34 free of water. The waterjet cutting head 1 can then be controlled (e.g., moved in the X and/or Y directions, and/or in other axes) to align the waterjet cutting head 1 with a desired feature of the workpiece. If the light alignment device 4 is coupled to the waterjet cutting head 1 at an aperture that is needed for use in cutting operations (e.g., an abrasive feed port), the light alignment device 4 can be decoupled from the waterjet cutting head 1 prior to commencing cutting operations. Alternatively, if the light alignment device 4 is coupled to the waterjet cutting head 1 at an aperture that is not needed for use in cutting operations, the light alignment device 4 can be left coupled to the waterjet cutting head 1.

FIG. 4 is a flow diagram of a process 400 for operating a waterjet cutting system in accordance with an embodiment of the disclosure. The process 400 begins at step 405, where a light alignment device is coupled to a waterjet cutting head of the waterjet cutting system. At step 410, the light alignment device is activated. At step 415, the light alignment device produces a beam of light that is directed through an axial passage of a mixing tube of the waterjet cutting head and impacts a workpiece. At step 420, the waterjet cutting system is positioned based upon the position of the light upon the workpiece. For example, the waterjet cutting head can be moved along any possible axis (e.g., X-axis, Y-axis, Z-axis, rotated, angled, etc.). As another example, the workpiece can be moved relative to the waterjet cutting head. Additionally or alternatively, both the waterjet cutting head and the workpiece can be positioned. At step 425, the light alignment device is deactivated. At step 430, the light alignment device is decoupled from the waterjet cutting head. At step 435, the waterjet cutting system begins cutting the workpiece. After step 435, the process 400 concludes.

In testing light alignment devices 4 with waterjet cutting systems, it has been observed that wear in the mixing tube 7 (e.g., wear in the mixing tube axial passage 34) can be accurately monitored by observing the size of the spot created by the light alignment device 4 at some distance (e.g., approximately 100 mm) from the tip of the mixing tube 7. In a new mixing tube 7 or a mixing tube 7 having no significant wear, the axial passage 34 has generally parallel interior walls, and so does the emerging beam 16. As the mixing tube 7 wears the axial passage 34 becomes tapered, with a top portion having a larger bore than a bottom portion. Such tapering allows some of the non-parallel rays in beam 16 to propagate down the mixing tube 7, generating a slightly divergent output beam 16. By observing the diameter of the beam 16 at some distance the taper in the mixing tube 7 can be visualized without having to remove the mixing tube 7 from the cutting head 1. If a parallel exit beam is desired regardless of the extent of mixing tube 7 wear, an aperture, such as an aperture from approximately 0.7 mm to approximately 1 mm in diameter can be used to constrain the width of the beam 16. The aperture can be installed between lens 12 and optical component 15, or at any other suitable location.

FIG. 5 is a flow diagram of a process 500 for determining the extent of wear of a waterjet cutting system mixing tube in accordance with an embodiment of the disclosure. The process 500 begins at step 505, where a light alignment device of the waterjet cutting system is activated. At step 510, the light alignment device produces a beam of light that is directed through an axial passage of a mixing tube of a waterjet cutting head of the waterjet cutting system and impacts a surface. At step 520 the area of light upon the surface is determined. For example, the surface may be a light-sensitive surface that generates one or more signals in response to light of a certain wavelength (e.g., the wavelength of light produced by the light alignment device) impacting the surface. The signals may be used to determine the area of light upon the surface. At step 520, the extent of wear of the mixing tube is determined based upon the area of the light. For example, a beam of light passing through a mixing tube having no wear may have an area of a certain number of mm². If the beam of light has an area that is greater than this certain number by a specified amount or percentage, the mixing tube may be determined to have excessive wear. Accordingly, the process 500 can be used to determine when a mixing tube needs to be replaced. After step 520, the process 500 concludes.

Those skilled in the art will appreciate that the steps shown in either of FIGS. 4 and 5 may be altered in a variety of ways. For example, the order of the steps may be rearranged; substeps may be performed in parallel; shown steps may be omitted, or other steps may be included; etc.

FIG. 6 is an isometric view of a waterjet cutting system 600 which can utilize various embodiments of the light alignment devices configured in accordance with the present disclosure. The waterjet cutting system 600 includes a base 605 and a mechanism 610 for moving a cutting head 1 in both the X and Y directions. The waterjet cutting system 600 may also include a pressurized water source, such as a pump (not shown in FIG. 6) that conveys highly pressurized water (e.g., water at a high pressure, such as about 15,000 psi to about 60,000 psi or more) to the cutting head 1. The waterjet cutting system 600 also includes an abrasive container 630 and an abrasive supply conduit 2 that conveys abrasives 635 from the abrasive container 630 to the cutting head 1. The waterjet cutting system 600 can also include a controller 615 that an operator may use to program or otherwise control the waterjet cutting system 600.

From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. Those skilled in the art will recognize that numerous liquids other than water can be used, and the recitation of a jet as comprising water should not necessarily be interpreted as a limitation. For example, fluids other than water can also be employed to cut materials that cannot be in contact with water. The customary term for the process of cutting with a fluid is “water-jet cutting” and the like, but the term “water-jet cutting” is not intended to exclude cutting by abrasive jets of fluid other than water.

Further, while advantages associated with certain embodiments have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the present disclosure. Accordingly, the inventions are not limited except as by the appended claims. 

1. A waterjet cutting system comprising: a high-pressure water source; a waterjet cutting head coupled to the high-pressure water source via a high-pressure water supply, the waterjet cutting head including an orifice configured to form a waterjet from high-pressure water provided by the high-pressure water source; and a mixing tube having an inlet aperture through which the waterjet enters the mixing tube, an exit aperture through which waterjet exits the mixing tube, and a passage between the inlet and exit apertures; and a light alignment device configured to be coupled to the waterjet cutting head, the light alignment device configured to generate a light beam that enters the mixing tube through the inlet aperture, passes through the passage, and exits the mixing tube through the exit aperture.
 2. The waterjet cutting system of claim 1 wherein the light alignment device includes at least one optical component configured to redirect the light beam prior to the light beam entering the mixing tube through the inlet aperture.
 3. The waterjet cutting system of claim 1 wherein the light alignment device includes at least one optical component configured to focus the light beam.
 4. The waterjet cutting system of claim 1, further comprising a pressurized air source coupled to waterjet cutting head, wherein the pressurized air source is configured to generate pressurized air that enters the mixing tube through the inlet aperture, passes through the passage, and exits the mixing tube through the exit aperture.
 5. The waterjet cutting system of claim 4 wherein the waterjet cutting head further includes a one-way valve configured to allow pressurized air from the pressurized air source to enter the waterjet cutting head.
 6. The waterjet cutting system of claim 1 wherein the light beam passes through the orifice prior to the light beam entering the mixing tube through the inlet aperture.
 7. The waterjet cutting system of claim 1 wherein the waterjet cutting head further includes an aperture in an external surface, and wherein at least a portion of the light alignment device is inserted into the aperture in the external surface.
 8. The waterjet cutting system of claim 7 wherein the aperture is an abrasive inlet aperture.
 9. The waterjet cutting system of claim 7 wherein the aperture is configured to be coupled to a vacuum assist device via a conduit.
 10. A fluid jet cutting system comprising: a fluid jet cutting head coupled to a fluid supply, the fluid jet cutting head including a mixing tube having a longitudinal bore through which cutting fluid is conveyed; and a light alignment device configured to be coupled to the cutting head and configured to generate light that passes through at least a portion of the longitudinal bore of the mixing tube.
 11. The fluid jet cutting system of claim 10 wherein the light alignment device includes at least one optical component configured to redirect the light prior to the light passing through the at least portion of the longitudinal bore of the mixing tube.
 12. The fluid jet cutting system of claim 10, further comprising a pressurized air source coupled to fluid jet cutting head, wherein the pressurized air source is configured to generate pressurized air that passes through the at least portion of the longitudinal bore of the mixing tube.
 13. The fluid jet cutting system of claim 10 wherein the fluid jet cutting head further includes an orifice configured to form a fluid jet, and wherein the light passes through the orifice prior to passing through the at least portion of the longitudinal bore of the mixing tube.
 14. The fluid jet cutting system of claim 10 wherein the fluid jet cutting head further includes an external surface and an aperture in the external surface, and wherein at least a portion of the light alignment device is inserted into the aperture in the external surface.
 15. The fluid jet cutting system of claim 14 wherein the aperture is an abrasive inlet aperture configured to selectively receive an abrasive supply conduit.
 16. A fluid jet cutting system comprising: means for flowing cutting fluid through a bore; and means for generating light that is directed through at least a portion of the bore.
 17. The fluid jet cutting system of claim 16 wherein the means for generating light includes means for redirecting the light prior to the light passing through the at least portion of the bore.
 18. The fluid jet cutting system of claim 16, further comprising means for providing pressurized air, wherein the means for providing pressurized air is configured to provide pressurized air that passes through the at least portion of the bore.
 19. The fluid jet cutting system of claim 16, further comprising means for forming a fluid jet, and wherein the light passes through the means for forming a fluid jet prior to the light passing through the at least portion of the bore.
 20. The fluid jet cutting system of claim 16 wherein the flowing has an aperture in an external surface, and wherein at least a portion of the means for generating light is inserted into the aperture in the external surface.
 21. The fluid jet cutting system of claim 20 wherein the aperture is an abrasive inlet aperture.
 22. A method of operating a fluid jet cutting system, the method comprising: generating a light beam; directing the light beam at a workpiece through at least a portion of a bore of a fluid jet cutting head; and based upon the position of the light beam upon the workpiece, cutting the workpiece with the fluid jet.
 23. The method of claim 22, further comprising: coupling the light alignment device to the fluid jet cutting head; after the directing, decoupling the light alignment device from the fluid jet cutting head; and after the decoupling, performing at least one fluid jet cutting operation.
 24. The method of claim 22 wherein generating a light beam includes generating a light beam by a light alignment device coupled to the fluid jet cutting head.
 25. The method of claim 22, further comprising directing the light beam using at least one optical component.
 26. A method of aligning a fluid jet with a point on an object, the method comprising sending a light beam toward the object through at least a portion of a fluid jet nozzle.
 27. The method of claim 25, further comprising performing at least one fluid jet cutting operation.
 28. The method of claim 25, further comprising generating the light beam by a light alignment device coupled to the fluid jet nozzle.
 29. A method of determining the extent of wear of a mixing tube of a fluid jet cutting head of a fluid jet cutting system, the method comprising: generating a light beam; directing the light beam at a surface through at least a portion of a bore of a mixing tube of the fluid jet cutting head; determining an area of the light beam upon the surface; and based upon the area of the light beam upon the surface, determining the extent of wear of the mixing tube.
 30. The method of claim 29 wherein directing the light beam at a surface through at least a portion of a bore of the mixing tube of the fluid jet cutting head includes directing the light beam at a light-sensitive surface through at least a portion of a bore of the mixing tube of the fluid jet cutting head, and wherein determining an area of the light upon the surface includes receiving signals from the light-sensitive surface indicating the area of the light beam. 